Clutch or brake device for an automatic transmission

ABSTRACT

Clutch or brake device for an automatic transmission comprising a support element such as a clutch drum having a cylindrical wall having splines and a clutch reaction plate carried by the support element. Localized welds fix the periphery of the plate to the splines of the support element.

United States Patent 1 Piret July 10, 1973 CLUTCH 0R BRAKE DEVICE FOR ANAUTOMATIC TRANSMISSION [75] Inventor: Jean Piret, Bougival, France {731Assignees: Automobiles Peugeot, Paris; Regie Nationale Des UsinesRenault, Billancourt, both of France [22] Filed: Oct. 12, 1971 [21]Appl. No.: 188,220

[30] Foreign Application Priority Data Nov. 4, 1970 France 7039716 [52]US. Cl 192/70.2, 188/715, 192/85 AA, 287/53 SS [51] lnttCl. Fl6d 13/ 52,Fl6d 13/68 [58] Field of Search l92/70.13, 70.2,

192185 AA; 74/446; 29/159.2; 188/71.1, 71.5, 73.3; 287/5204, 53 SS [56]References Cited UNITED STATES PATENTS 3,081,854 3/1963 Snyder.....'192/85 AAX Wilson, Sr. 29/159.2

866,364 9/1907 Hutchins 74/446 X 1,156,582 10/1915 Biggar 287/52041,495,604 5/1924 Lipe et al 192/70.13 1,732,965 10/1929 Carhart 192/70.22,345,037 3/1944 Gray 285/286 X 2,923,166 2/1960 Brindley et a1. 74/447X 3,230,616 1/1966 .lanssen 29/159.2 X

FOREIGN PATENTS OR APPLICATIONS 954,134 4/1964 Great Britain 192/70.2

Primary Examiner-A1lan D. Herrmann Attorney-Burns, Doane, Swecker &Mathis [5 7] ABSTRACT Clutch or brake device for an automatictransmission comprising a support element such as a clutch drum having acylindrical wall having splines and a clutch reaction plate carried bythe support element. Localized welds fix the periphery of the plate tothe splines of the support element.

6 Claims, 3 Drawing Figures CLUTCH OR BRAKE DEVICE FOR AN AUTOMATICTRANSMISSION The present invention relates to automatic transmissions orgear boxes and more particularly to the mounting of the clutch reactionplates employed in such transmissions.

It is known that automatic transmissions or transmissions having anautomatic control comprise brake and clutch devices whose selectiveactuation results in the required transmission ratio. These brakes orclutches comprise two alternating series of discs which are capable ofbeing pressed against each other under the effect of the pressureexerted by the piston of a hydraulic actuating device and moreover bearagainst a reaction plate which is usually fixed in a detachable mannerto a support element to which the discs of one of the two series ofdiscs are keyed. Due to the fact that conventional automatictransmissions are complicated and expensive mechanisms it is consideredabsolutely essential that these mechanisms be capable of being disrnamtled so as to enable a damaged or worn part to be replaced. The reactionplate is consequently held in position on its support element by aresiliently yieldable ring or circlip which is received in a groove inthe support element. Usually these support elements are constituted byrelatively-thin pressed-out sheet-metal members, so that the groovereceiving the resiliently yieldable ring is very shallow. Consequently,the machining of this groove and of the ring received therein must beextremely precise so that the ring does not disengage and escape fromthe groove under the effect of the force exerted on the reaction plate.It will be understood that a machine affording such precision isexpensive as concerns both the tooling required and the operating timeand this increases the cost of automatic transmissions.

An object of the invention is to remedy this drawback and provide anassembly between the reaction plate and its support element which iseasy to achieve but which is nonetheless strong and performs in asatisfactory manner and is capable of being dismantled and a reassembledif desired.

The invention provides a clutch or brake device for an automatictransmission comprising a support element which is splined on its innerand/or outer periphery, and a clutch reaction plate carried by thesupport element, wherein said plate is fixed to the support element bymeans of localized welds arranged around the periphery of said plate.

According to one embodiment, the plate has teeth, known per se, whichare adapted to the splines of the support element and the welds are madein the region of the crests of the teeth.

According to another embodiment, the plate has a smooth outer peripheryand is welded to the crests of the inner splines formed in the supportelement.

Further features and advantages of the invention will be apparent fromthe ensuing description with reference to the accompanying drawing.

In the drawing FIG. 1 is a partial sectional view of an automatictransmission or gear box including the device according to theinvention, and

FIGS. 2 and 3 are respectively partial cross-sectional views of twodevices according to the invention.

FIG. 1 shows a part of an automatic transmission or gear box having twosupport elements'such as clutch drums 1 and 2 provided with splines intheir lateral cylindrical walls. The two drums are of sheet metal andthe splines are formed by a press operation on both the inner peripheryand outer periphery, as can be seen in FIGS. 2 and 3. t

A first clutch E comprises two series of discs 3 and 4, the discs 3 ofthe first series being keyed to a flange 5 integral with an intermediateshaft of the transmission whereas the discs 4 of the second series areconnected to rotate with the drum 1. This clutch E is actuated by ahydraulic device having a piston 6 and the disc assembly bears against areaction plate 7 which is welded to the drum, for example in the mannershown at 8 in FIG. 2. r

In this embodiment, the reaction plate 7 has on its outer peripheryteeth which are engaged in the splines of the clutch drum constituting asupport element for the plate and the welds are made on every two orthree teeth so as to achieve a suitable interconnection between thereaction plate and the drum.

A second clutch E is disposed between the two drums 1 and 2 and also hastwo series of discs 9 and 10 respectively keyed to the drums I and 2.This clutch is actuated by a piston 1 l and there is provided areactionplate 12 which is also welded to the end of the drum 2. It .will beobserved that in the case of clutch E the welds are effected through thecylindrical wall of the drum whereas in the case of the clutch E thesewelds are effected at the end, for example by electron beam welding. Itwill be understood that any suitable welding process may be employed.

In the embodiment shown in FIG. 3, the production of the reaction plate7a has been still further simplified by making this plate with a smoothouter wall, the welds being then made at along the inner periphery ofthe drum 1a on the crests of the inner splines.

Bearing in mind that there is an ever-increasing tendency to standardizemanufacture of automatic transmissions or gear boxes so as to reduceproduction costs, it may be considered that it is not essential that thereaction plate of the clutch be fixed to the drum in a detachablemanner. Indeed, the labour costs for dismantling and replacing'a damagedpart may be at least as much as the cost of a sub-assembly constitutedfor example by the drum, the clutch and theactuating piston.

However, in the device according to the inveition, it is possible, ifdesired, to achieve this dismantling in a simple manner notwithstandingthe welded connection between the plate and the drum, since thelocalized or spot welds are not made on every tooth and spline of thedrum and plate. Indeed, it is sufficient to machine, for example mill,the regions in which the welds are made. Fresh localized welds areeffected after reassembly in the region of the teeth which had not beenemployed for the first welds. According to a modification, all the weldsmay be sheared off simultaneously by a press operation which eliminatesthe machining operation.

Having now descrived my invention what I claim and desire to secure byLetters Patent is 1 1. A clutch or brake device for an automatictransmission,comprising a support. element having a cy lindrical walland splines on a periphery of said cylindrical wall, a clutch reactionplate carried by said support element, and having peripheral portionsengaging splines having inner crest portions, said outer periphery I ofsaid plate being welded to at least some of said inner crest portions.

4. A device as claimed in claim 1, wherein said welds are made throughsaid wall of the support element.

5. A device as claimed in claim 1, wherein said welds are made throughan end of said support element.

6. A device as claimed in claim 5, wherein said welds are made by anelectron beam welding.

1. A clutch or brake device for an automatic transmission, comprising asupport element having a cylindrical wall and splines on a periphery ofsaid cylindrical wall, a clutch reaction plate carried by said supportelement, and having peripheral portions engaging said splines, andlocalized discrete welds fixing said plate to said support element, saidwelds being arrangeD around said peripheral portions of said plate.
 2. Adevice as claimed in claim 1, wherein said plate has teeth adapted tosaid splines, said teeth having crest portions engaging correspondingportions of said splines and said welds being made radially in theregion of crest portions.
 3. A device as claimed in claim 1, whereinsaid plate has a smooth outer periphery and said support element hasinner splines on an inner periphery of said wall, said splines havinginner crest portions, said outer periphery of said plate being welded toat least some of said inner crest portions.
 4. A device as claimed inclaim 1, wherein said welds are made through said wall of the supportelement.
 5. A device as claimed in claim 1, wherein said welds are madethrough an end of said support element.
 6. A device as claimed in claim5, wherein said welds are made by an electron beam welding.